In mobile communication systems, information used upon establishing connection or during communication and information about other systems are broadcast in advance. These kinds of information are referred to as broadcast information (system information).
Broadcast information defined in IMT-2000 (International Mobile Telecommunications 2000) is classified into a master information block (MIB) and system information blocks (SIBs) associated with the MIB.
The master information block includes transmission timing of each system information block and a value tag indicating whether information is modified. The system information blocks are defined according to their properties. For example, information about the configuration of a common channel and information about regulations are defined in different system information blocks (see TS25.331 V6.10.0 8.1.1).
When broadcast information is transmitted on a shared channel, the master information block and the system information blocks are transmitted on a shared data channel. On the other hand, the size of each system information block and information about resource allocation are transmitted on a signaling control channel or signaling control channels. It should be noted that one or more signaling control channels may be defined within a cell. The number of signaling control channels corresponds to the number of users capable of transmitting data at the same time (see TS25.212 V6.5.0 4.6).